The present invention relates to a display device and more particularly, to a display device that can easily move, enlarge, or reduce a screen.
In recent years, the electronic display has played an extremely important role in the computerized society, and has widely been used for various applications both in industrial and consumer fields. The electronic display converts an electric signal outputted from various kinds of electronic equipment to an optical information signal which can visually be recognized by human. As the electronic display, there have been known displays a cathode-ray tube display (CRT), a plasma display (PDP), and an electroluminescent display (ELD) each referred to as a light-emitting type one, and a liquid crystal display (LCD) or an electrochemical display (ECD) referred to as a light-receiving type one.
Also in recent years, in association with rapid development in the fields of IC and LSI, various types of small-sized, light-weight and power-saving display unit have been developed, and at the same time, social needs for display units which are thin and light-weight can be driven with a low voltage at a low power-consumption rate have been increasing. Further, it has been strongly desired to develop a display unit which can respond to rapid increase in an amount of information to be processed. Especially, with progress in the multimedia technology, the electronic display has increased its importance as an indispensable item for accessing a cyber space, and a larger size of screen with higher resolution are desired further more strongly.
However, an image transfer system in the conventional type of electronic display units as described above is based on the scanning line system in which image data is continuously transmitted with preset resolution as well as with a preset number of scanning lines, and this conventional type of display unit can not basically support a case when a size of a screen is arbitrarily changed and the resolution (the number of display elements in the horizontal direction) as well as the number of scanning lines (the number of display elements in the vertical direction) are changed, and for this reason, it has been impossible for manufacturers to materialize the idea itself that the size of a screen is arbitrarily changeable by a user.
For example, even when the size of a screen is made larger and resolution (the number of display elements in the horizontal direction) as well as the number of scanning lines (the number of display elements in the vertical direction) are increased, the resolution and the number of scanning lines of image data to be sent in the scanning line system remain the same, so that it is impossible to display an image by using the entire screen. Also, when it is tried to forcefully display the image, the image is displayed only on a part of the screen in response to the resolution as well as to the number of scanning lines of the transferred image data. In other words, even when the size of a screen is made larger, resolution of an image to be displayed on the screen can not be made higher.
As an invention for solving the problems as described above, there is the one already applied by the present applicant (Japanese Patent Laid-Open Publication No. HEI 9-144296). For more details, the application should be referred to. It is an object of the present invention to provide an effective screen display system based on the concepts as recited in the above patent application.
The display device according to the present invention comprises a display unit for arranging display elements and constructing a screen by adding an absolute address to each of the display elements; and an address control unit for converting the absolute address to a relative address capable of specifying a screen on the display unit and changing the relative address, so that, when a screen is to be specified according to a relative address, it is possible to change a screen to be specified by changing this relative address. Through the steps described above, it is possible to easily change a position of a screen as well as a screen size without any change in the display data to be supplied only by changing the relative address.
In the display device according to the present invention, an image is displayed by dividing a screen according to a specified format, repeating the division thereof one after another by further dividing each of the divided unit areas, specifying each of the divided unit areas with bits, and supplying display data to each divided unit area, so that it is possible to change a position or a size of the divided unit area by way of operating bits. Namely, as a divided unit area can be specified with bits, when these bits are operated, also the specified divided unit area can be changed. And for this reason, it is possible to easily change a position or a size of a screen by way of operating bits.
In the display device according to the present invention, an image is displayed on a screen by arranging display elements at a matrix to form a screen, repeatedly dividing the screen, allocating an address to each divided unit area each time division is executed, specifying each of the divided unit areas according to each of the addresses, and supplying display data to the specified divided unit area. Then the image can be moved, enlarged, or reduced by changing the address. With the configuration as described above, it is possible to easily move a screen without any change in the display data only by way of changing the address.